Northern lights

Northern LightIf all naturally occuring heavenly phenomena, few come close to a night with a magnificent northern lights display. Flickering curtains of dancing light against the dark skies, northern lights is certainly one of the most spectacular of nature’s phenomena. The left picture shows a herd of stars makes tracks across northern lights in a time exposure taken when the temperature reached minus 58° F. [minus 50° C.].” Northern lights is the name of a light phenomenon often seen in the northern regions. The lights have been around since Earth formed an atmosphere -the dinosaurs saw it, early humans saw it and our descendants will se it. The scientific name for the phenomenon is “Aurora Borealis”, aurora for short. Auroras are caused by the interaction of energetic particles (electrons and protons) of the solar wind with atoms of the upper atmosphere. Such interaction is confined for the most part to high latitudes in oval-shaped zones that surround Earth’s magnetic poles and maintain a more or less fixed orientation with respect to the Sun. During periods of low solar activity, the auroral zones shift poleward. During periods of intense solar activity, auroras occasionally extend to the middle latitudes; for example, the aurora borealis has been seen as far south as 40° latitude in the United States. Auroral emissions typically occur at altitudes of about 100 km (60 miles); however, they may occur anywhere between 80 and 250 km (about 50 to 155 miles) above Earth’s surface.

Aurora borealis and forest in winter near Chena River State Recreation Area, Fairbanks, Alaska, USA